Const HWND_BROADCAST As Integer = &HFFFF
Const SC_MONITORPOWER As Integer = &HF170
Const WM_SYSCOMMAND As Short = &H112S
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal Hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Private Sub Spegni() Handles Button1.Click
        SendMessage(CType(HWND_BROADCAST, IntPtr), WM_SYSCOMMAND, SC_MONITORPOWER, 2)
End Sub